yeah if you are staying for an extended period over a weekend it won't matter if it's summer or not you are gonna get fucking railed on the rate wherever you go...if you are a "retail customer" I think you're gonna be lucky to pay less than $300 even at a place like resorts...the weekends are the only time post labor day/pre-memorial day that sees any volume in AC...I used to laugh that when I was working at the evil empire the rates at ballys were like $400+/night for retail customers on weekends in the offseason...you have to be smoking crack to pay that kinda money to stay at a shithole like ballys...not that its great to do at Borgata, but at least its Borgata and the rooms are gonna be circa 2017 instead of circa 1990s like they are at ballys...
don't know if you are gonna have a car down there, but if you just plan on playing poker you might want to investigate getting a room at one of the shore towns around AC and just driving in...that fucking blows, especially if you want to play in a cash game and have a few drinks but i'd bet you could probably get a decent rate since the shore is a ghost town post-labor day...